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This article mainly introduces the Spring Boot jpa Service layer example analysis, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let the editor take you to understand it.

Example:

Package com.fei.service.impl;import java.util.ArrayList;import java.util.List;import javax.persistence.criteria.CriteriaBuilder;import javax.persistence.criteria.CriteriaQuery;import javax.persistence.criteria.Predicate;import javax.persistence.criteria.Root;import org.springframework.beans.BeanUtils;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.data.domain.Page;import org.springframework.data.domain.Pageable;import org.springframework.data.jpa.domain.Specification;import org.springframework.stereotype.Service;import com.fei.NotFoundException Import com.fei.po.Blog;import com.fei.po.Type;import com.fei.repository.BlogRepository;import com.fei.service.BlogService;/** * Created by zxf on October 3, 2019 * / @ Servicepublic class BlogServiceImpl implements BlogService {@ Autowired private BlogRepository blogRepository; / * query a blog according to id * * @ param id * @ return * / @ Override public Blog getBlog (Long id) {return blogRepository.findById (id). Get () } / * Multi-conditional dynamic query blog list * * @ param pageable * @ param blog * @ return * / @ Override public Page listBlog (Pageable pageable, Blog blog) {return blogRepository.findAll (new Specification () {@ Override public Predicate toPredicate (Root root, CriteriaQuery cq, CriteriaBuilder cb) {List predicates = new ArrayList (); String title = blog.getTitle () If (! ".equals (title) & & title! = null) {predicates.add (cb.like (root.get (" title "),"% "+ title +"% "));} Long id = blog.getType (). GetId (); if (id! = null) {predicates.add (cb.equal (root.get (" type "). Get (" id "), id)) } boolean isRecommend = blog.isRecommend (); if (isRecommend) {predicates.add (cb.equal (root.get ("recommend"), isRecommend));} cq.where (predicates.toArray (new Predicate [predicates.size ()]); return null;}}, pageable) } / * Save a blog * * @ param blog * @ return * / @ Override public Blog saveBlog (Blog blog) {return blogRepository.save (blog) Update a blog, first echo * * @ param id * @ param blog * @ return * / @ Override public Blog updateBlog (Long id, Blog blog) {Blog b = blogRepository.findById (id). Get (); if (b = = null) {throw new NotFoundException ("the blog you want to update does not exist!") ;} BeanUtils.copyProperties (b, blog); return blogRepository.save (blog);} / * Delete a blog according to id * * @ param id * / @ Override public void deleteBlog (Long id) {blogRepository.deleteById (id) }} Thank you for reading this article carefully. I hope the article "sample Analysis of the Spring Boot jpa Service layer" shared by the editor will be helpful to you. At the same time, I also hope that you will support us and pay attention to the industry information channel. More related knowledge is waiting for you to learn!

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